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This module provides the ConfigParser class which implements a basic
configuration language which provides a structure similar to what’s found in
Microsoft Windows INI files. You can use this to write Python programs which
can be customized by end users easily.

Note

This library does not interpret or write the value-type prefixes used in
the Windows Registry extended version of INI syntax.

The structure of INI files is described in the following section. Essentially, the file
consists of sections, each of which contains keys with values.
configparser classes can read and write such files. Let’s start by
creating the above configuration file programatically.

As we can see above, the API is pretty straightforward. The only bit of magic
involves the DEFAULT section which provides default values for all other
sections [1]. Note also that keys in sections are
case-insensitive and stored in lowercase [1].

Extracting Boolean values is not that simple, though. Passing the value
to bool() would do no good since bool('False') is still
True. This is why config parsers also provide getboolean().
This method is case-insensitive and recognizes Boolean values from
'yes'/'no', 'on'/'off' and '1'/'0'[1].
For example:

Please note that default values have precedence over fallback values.
For instance, in our example the 'CompressionLevel' key was
specified only in the 'DEFAULT' section. If we try to get it from
the section 'topsecret.server.com', we will always get the default,
even if we specify a fallback:

>>> topsecret.get('CompressionLevel','3')'9'

One more thing to be aware of is that the parser-level get() method
provides a custom, more complex interface, maintained for backwards
compatibility. When using this method, a fallback value can be provided via
the fallback keyword-only argument:

>>> config.get('bitbucket.org','monster',... fallback='No such things as monsters')'No such things as monsters'

The same fallback argument can be used with the getint(),
getfloat() and getboolean() methods, for example:

A configuration file consists of sections, each led by a [section] header,
followed by key/value entries separated by a specific string (= or : by
default [1]). By default, section names are case sensitive but keys are not
[1]. Leading and trailing whitespace is removed from keys and values.
Values can be omitted, in which case the key/value delimiter may also be left
out. Values can also span multiple lines, as long as they are indented deeper
than the first line of the value. Depending on the parser’s mode, blank lines
may be treated as parts of multiline values or ignored.

Configuration files may include comments, prefixed by specific
characters (# and ; by default [1]). Comments may appear on
their own on an otherwise empty line, possibly indented. [1]

For example:

[Simple Values]
key=value
spaces in keys=allowed
spaces in values=allowed as well
spaces around the delimiter = obviously
you can also use : to delimit keys from values
[All Values Are Strings]
values like this: 1000000
or this: 3.14159265359
are they treated as numbers? : no
integers, floats and booleans are held as: strings
can use the API to get converted values directly: true
[Multiline Values]
chorus: I'm a lumberjack, and I'm okay
I sleep all night and I work all day
[No Values]
key_without_value
empty string value here =
[You can use comments]
# like this
; or this
# By default only in an empty line.
# Inline comments can be harmful because they prevent users
# from using the delimiting characters as parts of values.
# That being said, this can be customized.
[Sections Can Be Indented]
can_values_be_as_well = True
does_that_mean_anything_special = False
purpose = formatting for readability
multiline_values = are
handled just fine as
long as they are indented
deeper than the first line
of a value
# Did I mention we can indent comments, too?

The default implementation used by ConfigParser. It enables
values to contain format strings which refer to other values in the same
section, or values in the special default section [1]. Additional default
values can be provided on initialization.

In the example above, ConfigParser with interpolation set to
BasicInterpolation() would resolve %(home_dir)s to the value of
home_dir (/Users in this case). %(my_dir)s in effect would
resolve to /Users/lumberjack. All interpolations are done on demand so
keys used in the chain of references do not have to be specified in any
specific order in the configuration file.

With interpolation set to None, the parser would simply return
%(my_dir)s/Pictures as the value of my_pictures and
%(home_dir)s/lumberjack as the value of my_dir.

An alternative handler for interpolation which implements a more advanced
syntax, used for instance in zc.buildout. Extended interpolation is
using ${section:option} to denote a value from a foreign section.
Interpolation can span multiple levels. For convenience, if the section:
part is omitted, interpolation defaults to the current section (and possibly
the default values from the special section).

For example, the configuration specified above with basic interpolation,
would look like this with extended interpolation:

Mapping protocol access is a generic name for functionality that enables using
custom objects as if they were dictionaries. In case of configparser,
the mapping interface implementation is using the
parser['section']['option'] notation.

parser['section'] in particular returns a proxy for the section’s data in
the parser. This means that the values are not copied but they are taken from
the original parser on demand. What’s even more important is that when values
are changed on a section proxy, they are actually mutated in the original
parser.

configparser objects behave as close to actual dictionaries as possible.
The mapping interface is complete and adheres to the
MutableMapping ABC.
However, there are a few differences that should be taken into account:

By default, all keys in sections are accessible in a case-insensitive manner
[1]. E.g. foroptioninparser["section"] yields only optionxform‘ed
option key names. This means lowercased keys by default. At the same time,
for a section that holds the key 'a', both expressions return True:

"a"inparser["section"]"A"inparser["section"]

All sections include DEFAULTSECT values as well which means that
.clear() on a section may not leave the section visibly empty. This is
because default values cannot be deleted from the section (because technically
they are not there). If they are overriden in the section, deleting causes
the default value to be visible again. Trying to delete a default value
causes a KeyError.

DEFAULTSECT cannot be removed from the parser:

trying to delete it raises ValueError,

parser.clear() leaves it intact,

parser.popitem() never returns it.

parser.get(section,option,**kwargs) - the second argument is not
a fallback value. Note however that the section-level get() methods are
compatible both with the mapping protocol and the classic configparser API.

parser.items() is compatible with the mapping protocol (returns a list of
section_name, section_proxy pairs including the DEFAULTSECT). However,
this method can also be invoked with arguments: parser.items(section,raw,vars). The latter call returns a list of option, value pairs for
a specified section, with all interpolations expanded (unless
raw=True is provided).

The mapping protocol is implemented on top of the existing legacy API so that
subclasses overriding the original interface still should have mappings working
as expected.

There are nearly as many INI format variants as there are applications using it.
configparser goes a long way to provide support for the largest sensible
set of INI styles available. The default functionality is mainly dictated by
historical background and it’s very likely that you will want to customize some
of the features.

The most common way to change the way a specific config parser works is to use
the __init__() options:

defaults, default value: None

This option accepts a dictionary of key-value pairs which will be initially
put in the DEFAULT section. This makes for an elegant way to support
concise configuration files that don’t specify values which are the same as
the documented default.

Hint: if you want to specify default values for a specific section, use
read_dict() before you read the actual file.

This option has a major impact on how the mapping protocol will behave and how
the written configuration files look. With the default ordered
dictionary, every section is stored in the order they were added to the
parser. Same goes for options within sections.

An alternative dictionary type can be used for example to sort sections and
options on write-back. You can also use a regular dictionary for performance
reasons.

Please note: there are ways to add a set of key-value pairs in a single
operation. When you use a regular dictionary in those operations, the order
of the keys may be random. For example:

Some configuration files are known to include settings without values, but
which otherwise conform to the syntax supported by configparser. The
allow_no_value parameter to the constructor can be used to
indicate that such values should be accepted:

Delimiters are substrings that delimit keys from values within a section. The
first occurrence of a delimiting substring on a line is considered a delimiter.
This means values (but not keys) can contain the delimiters.

Comment prefixes are strings that indicate the start of a valid comment within
a config file. comment_prefixes are used only on otherwise empty lines
(optionally indented) whereas inline_comment_prefixes can be used after
every valid value (e.g. section names, options and empty lines as well). By
default inline comments are disabled and '#' and ';' are used as
prefixes for whole line comments.

Changed in version 3.2: In previous versions of configparser behaviour matched
comment_prefixes=('#',';') and inline_comment_prefixes=(';',).

Please note that config parsers don’t support escaping of comment prefixes so
using inline_comment_prefixes may prevent users from specifying option
values with characters used as comment prefixes. When in doubt, avoid setting
inline_comment_prefixes. In any circumstances, the only way of storing
comment prefix characters at the beginning of a line in multiline values is to
interpolate the prefix, for example:

When set to True, the parser will not allow for any section or option
duplicates while reading from a single source (using read_file(),
read_string() or read_dict()). It is recommended to use strict
parsers in new applications.

Changed in version 3.2: In previous versions of configparser behaviour matched
strict=False.

empty_lines_in_values, default value: True

In config parsers, values can span multiple lines as long as they are
indented more than the key that holds them. By default parsers also let
empty lines to be parts of values. At the same time, keys can be arbitrarily
indented themselves to improve readability. In consequence, when
configuration files get big and complex, it is easy for the user to lose
track of the file structure. Take for instance:

[Section]key=multiline value with a gotchathis=is still a part of the multiline value of 'key'

This can be especially problematic for the user to see if she’s using a
proportional font to edit the file. That is why when your application does
not need values with empty lines, you should consider disallowing them. This
will make empty lines split keys every time. In the example above, it would
produce two keys, key and this.

The convention of allowing a special section of default values for other
sections or interpolation purposes is a powerful concept of this library,
letting users create complex declarative configurations. This section is
normally called "DEFAULT" but this can be customized to point to any
other valid section name. Some typical values include: "general" or
"common". The name provided is used for recognizing default sections when
reading from any source and is used when writing configuration back to
a file. Its current value can be retrieved using the
parser_instance.default_section attribute and may be modified at runtime
(i.e. to convert files from one format to another).

interpolation, default value: configparser.BasicInterpolation

Interpolation behaviour may be customized by providing a custom handler
through the interpolation argument. None can be used to turn off
interpolation completely, ExtendedInterpolation() provides a more
advanced variant inspired by zc.buildout. More on the subject in the
dedicated documentation section.
RawConfigParser has a default value of None.

More advanced customization may be achieved by overriding default values of
these parser attributes. The defaults are defined on the classes, so they
may be overriden by subclasses or by attribute assignment.

By default when using getboolean(), config parsers consider the
following values True: '1', 'yes', 'true', 'on' and the
following values False: '0', 'no', 'false', 'off'. You
can override this by specifying a custom dictionary of strings and their
Boolean outcomes. For example:

This method transforms option names on every read, get, or set
operation. The default converts the name to lowercase. This also
means that when a configuration file gets written, all keys will be
lowercase. Override this method if that’s unsuitable.
For example:

A compiled regular expression used to parse section headers. The default
matches [section] to the name "section". Whitespace is considered part
of the section name, thus [larch] will be read as a section of name
"larch". Override this attribute if that’s unsuitable. For example:

While ConfigParser objects also use an OPTCRE attribute for recognizing
option lines, it’s not recommended to override it because that would
interfere with constructor options allow_no_value and delimiters.

Mainly because of backwards compatibility concerns, configparser
provides also a legacy API with explicit get/set methods. While there
are valid use cases for the methods outlined below, mapping protocol access is
preferred for new projects. The legacy API is at times more advanced,
low-level and downright counterintuitive.

An example of writing to a configuration file:

importconfigparserconfig=configparser.RawConfigParser()# Please note that using RawConfigParser's set functions, you can assign# non-string values to keys internally, but will receive an error when# attempting to write to a file or when you get it in non-raw mode. Setting# values using the mapping protocol or ConfigParser's set() does not allow# such assignments to take place.config.add_section('Section1')config.set('Section1','an_int','15')config.set('Section1','a_bool','true')config.set('Section1','a_float','3.1415')config.set('Section1','baz','fun')config.set('Section1','bar','Python')config.set('Section1','foo','%(bar)s is %(baz)s!')# Writing our configuration file to 'example.cfg'withopen('example.cfg','w')asconfigfile:config.write(configfile)

An example of reading the configuration file again:

importconfigparserconfig=configparser.RawConfigParser()config.read('example.cfg')# getfloat() raises an exception if the value is not a float# getint() and getboolean() also do this for their respective typesa_float=config.getfloat('Section1','a_float')an_int=config.getint('Section1','an_int')print(a_float+an_int)# Notice that the next output does not interpolate '%(bar)s' or '%(baz)s'.# This is because we are using a RawConfigParser().ifconfig.getboolean('Section1','a_bool'):print(config.get('Section1','foo'))

importconfigparsercfg=configparser.ConfigParser()cfg.read('example.cfg')# Set the optional *raw* argument of get() to True if you wish to disable# interpolation in a single get operation.print(cfg.get('Section1','foo',raw=False))# -> "Python is fun!"print(cfg.get('Section1','foo',raw=True))# -> "%(bar)s is %(baz)s!"# The optional *vars* argument is a dict with members that will take# precedence in interpolation.print(cfg.get('Section1','foo',vars={'bar':'Documentation','baz':'evil'}))# The optional *fallback* argument can be used to provide a fallback valueprint(cfg.get('Section1','foo'))# -> "Python is fun!"print(cfg.get('Section1','foo',fallback='Monty is not.'))# -> "Python is fun!"print(cfg.get('Section1','monster',fallback='No such things as monsters.'))# -> "No such things as monsters."# A bare print(cfg.get('Section1', 'monster')) would raise NoOptionError# but we can also use:print(cfg.get('Section1','monster',fallback=None))# -> None

Default values are available in both types of ConfigParsers. They are used in
interpolation if an option used is not defined elsewhere.

importconfigparser# New instance with 'bar' and 'baz' defaulting to 'Life' and 'hard' eachconfig=configparser.ConfigParser({'bar':'Life','baz':'hard'})config.read('example.cfg')print(config.get('Section1','foo'))# -> "Python is fun!"config.remove_option('Section1','bar')config.remove_option('Section1','baz')print(config.get('Section1','foo'))# -> "Life is hard!"

The main configuration parser. When defaults is given, it is initialized
into the dictionary of intrinsic defaults. When dict_type is given, it
will be used to create the dictionary objects for the list of sections, for
the options within a section, and for the default values.

When delimiters is given, it is used as the set of substrings that
divide keys from values. When comment_prefixes is given, it will be used
as the set of substrings that prefix comments in otherwise empty lines.
Comments can be indented. When inline_comment_prefixes is given, it will be
used as the set of substrings that prefix comments in non-empty lines.

When strict is True (the default), the parser won’t allow for
any section or option duplicates while reading from a single source (file,
string or dictionary), raising DuplicateSectionError or
DuplicateOptionError. When empty_lines_in_values is False
(default: True), each empty line marks the end of an option. Otherwise,
internal empty lines of a multiline option are kept as part of the value.
When allow_no_value is True (default: False), options without
values are accepted; the value held for these is None and they are
serialized without the trailing delimiter.

When default_section is given, it specifies the name for the special
section holding default values for other sections and interpolation purposes
(normally named "DEFAULT"). This value can be retrieved and changed on
runtime using the default_section instance attribute.

Interpolation behaviour may be customized by providing a custom handler
through the interpolation argument. None can be used to turn off
interpolation completely, ExtendedInterpolation() provides a more
advanced variant inspired by zc.buildout. More on the subject in the
dedicated documentation section.

All option names used in interpolation will be passed through the
optionxform() method just like any other option name reference. For
example, using the default implementation of optionxform() (which
converts option names to lower case), the values foo%(bar)s and foo%(BAR)s are equivalent.

Add a section named section to the instance. If a section by the given
name already exists, DuplicateSectionError is raised. If the
default section name is passed, ValueError is raised. The name
of the section must be a string; if not, TypeError is raised.

Attempt to read and parse a list of filenames, returning a list of
filenames which were successfully parsed. If filenames is a string, it
is treated as a single filename. If a file named in filenames cannot
be opened, that file will be ignored. This is designed so that you can
specify a list of potential configuration file locations (for example,
the current directory, the user’s home directory, and some system-wide
directory), and all existing configuration files in the list will be
read. If none of the named files exist, the ConfigParser
instance will contain an empty dataset. An application which requires
initial values to be loaded from a file should load the required file or
files using read_file() before calling read() for any
optional files:

Load configuration from any object that provides a dict-like items()
method. Keys are section names, values are dictionaries with keys and
values that should be present in the section. If the used dictionary
type preserves order, sections and their keys will be added in order.
Values are automatically converted to strings.

Optional argument source specifies a context-specific name of the
dictionary passed. If not given, <dict> is used.

Get an option value for the named section. If vars is provided, it
must be a dictionary. The option is looked up in vars (if provided),
section, and in DEFAULTSECT in that order. If the key is not found
and fallback is provided, it is used as a fallback value. None can
be provided as a fallback value.

All the '%' interpolations are expanded in the return values, unless
the raw argument is true. Values for interpolation keys are looked up
in the same manner as the option.

Changed in version 3.2: Arguments raw, vars and fallback are keyword only to protect
users from trying to use the third argument as the fallback fallback
(especially when using the mapping protocol).

A convenience method which coerces the option in the specified section
to a Boolean value. Note that the accepted values for the option are
'1', 'yes', 'true', and 'on', which cause this method to
return True, and '0', 'no', 'false', and 'off', which
cause it to return False. These string values are checked in a
case-insensitive manner. Any other value will cause it to raise
ValueError. See get() for explanation of raw, vars and
fallback.

Write a representation of the configuration to the specified file
object, which must be opened in text mode (accepting strings). This
representation can be parsed by a future read() call. If
space_around_delimiters is true, delimiters between
keys and values are surrounded by spaces.

Transforms the option name option as found in an input file or as passed
in by client code to the form that should be used in the internal
structures. The default implementation returns a lower-case version of
option; subclasses may override this or client code can set an attribute
of this name on instances to affect this behavior.

You don’t need to subclass the parser to use this method, you can also
set it on an instance, to a function that takes a string argument and
returns a string. Setting it to str, for example, would make option
names case sensitive:

cfgparser=ConfigParser()cfgparser.optionxform=str

Note that when reading configuration files, whitespace around the option
names is stripped before optionxform() is called.

If the given section exists, set the given option to the specified value;
otherwise raise NoSectionError. While it is possible to use
RawConfigParser (or ConfigParser with raw parameters
set to true) for internal storage of non-string values, full
functionality (including interpolation and output to files) can only be
achieved using string values.

This method lets users assign non-string values to keys internally. This
behaviour is unsupported and will cause errors when attempting to write
to a file or get it in non-raw mode. Use the mapping protocol API
which does not allow such assignments to take place.

Exception raised by strict parsers if a single option appears twice during
reading from a single file, string or dictionary. This catches misspellings
and case sensitivity-related errors, e.g. a dictionary may have two keys
representing the same case-insensitive configuration key.